Preheat Oven
Preheat your oven to 325°F (160°C).
Season and Sear the Ribs
Generously season short ribs with salt and pepper. In a large Dutch oven, heat olive oil over medium-high. Sear the ribs in batches until browned on all sides, about 3–4 minutes per side. Transfer to a plate.
Sauté Aromatics
In the same pot, add onion, carrots, and celery. Cook 5–6 minutes until softened. Add garlic and tomato paste; cook another 1–2 minutes until fragrant.
Deglaze and Build the Sauce
Pour in red wine, scraping up brown bits from the bottom. Simmer 5 minutes to reduce slightly. Stir in beef broth and cranberries. Return ribs to the pot. Add rosemary, thyme, and bay leaf.
Braise
Cover with a tight-fitting lid and place in the oven. Braise for 2½ to 3 hours, or until the meat is fork-tender and falling off the bone.
Finish the Sauce
Remove the ribs and herbs. Skim fat from the surface. Simmer the sauce on the stovetop to thicken slightly, if desired. Taste and adjust seasoning.
Serve
Serve ribs over mashed potatoes, creamy polenta, or crusty bread with plenty of sauce spooned over top.